The use of metering valves in such installations is widespread and is intended to reduce the amount of water wasted when such valves are actuated. Conservation of water, particularly in certain geographic areas, is of paramount importance where there is a scarcity of water and/or the cost of water is inordinately high.
Various metering valves have heretofore been used for such installations, however, such valves have been beset with one or more of the following shortcomings: a) they are highly susceptible to malfunction; b) they are difficult to service and maintain; c) they are of costly and complex construction; d) they are awkward and difficult to install and require numerous special fittings and the need for special tools; e) replacement of the piston assembly requires substantial disassembly of the valve component; and f) substantial manual force is required to actuate the valve.
While my prior U.S. Pat. No. 4,991,819, dated Feb. 12, 1991, avoids most, if not all, of the foregoing shortcomings, it nevertheless embodies numerous components which increase the initial costs of manufacture and assembly. Furthermore, because of such components, the installer and supplier are frequently required to maintain a large inventory of spare components. Alignment and relative adjustment of the valve components sometimes become a frustrating and time-consuming operation particularly to an untrained installer.